Framework: Add Home/Back buttons available for rebinding (1/2)

Finally, we can disable or rebind all hardware buttons!
Also adds Expanded desktop toggle and Notification shade toggle

Change-Id: I0ca51c25e8434696a514fd1ef1e1e33543bf066a
Fix and cleanup Expanded Desktop Mode

no need to call state and mode several times from provider settings.
Cleaned up.

Also fix for the ugly lockscreen gap on expanded desktop
mode 1 and 3

And fix that mode changes reflects directly to the screen if
expanded state = 1

cheers

Change-Id: I8cc0d936af270d72f2fb5c005a28c575576d894b